Multi-wall bag



B- P. LOKEY MULTI-WALL BAG Nov. 16, 1965 2 Sheets-Sheet 1 Filed May 11,1964 INVENTOR. Bur/re P. Lo/rey BY ATTORNEY B. P. LOKEY Nov. 16, 1965MULTI-WALL BAG 2 Sheets-Sheet 2 Filed May 11, 1964 T e m mL IPJ F 5ATTORNEY United States Patent 3,217,970 MULTI-WALL BAG Burke P. Lokey,Metairie, La, assignor to West Virginia Pulp and Paper Company, NewYork, N.Y., a corporation of Delaware Filed May 11, 1964, Ser. No.366,404 9 Claims. (Cl. 229--62) The present invention relates tomulti-wall bags and is particularly directed to improvements in bags ofthe type disclosed in my co-pending application, Serial No. 216,388,filed August 13, 1962.

In the bag disclosed therein, a particular stepped end configuration isprovided which permits the formation of strong end closures in amulti-wall, gusseted bag by a simple folding and sealing operation. Thisbag is, therefore, well suited for use in packaging heavy bulk productsby means of automatic packaging apparatus; wherein strength andsimplicity of end closure formation is essential. In this bag, inaddition to the advantages of strength and simplicity in formation, theends are so designed that the top and bottom of the bag blanks areidentical but reversed in shape; whereby the blanks may be formed from acontinuous web of material without waste.

While bags of this type are thus, well suited for the packaging of mostmaterials, it has been found that in the packaging of particularly finegranular materials, liquids and other products that flow quite readilyand/ or are easily aerated, some leakage of the product may occur at thejuncture of the transverse edge of the bag wall and the longitudinaledge of the adjacent gusset. This results, because at this juncture thecomplete sealing of the interior of the bag is dependent entirely uponthe maintenance of a continuous line of adhesion. Thus, in subsequenthandling of the bag, for example, a slight separation of the adheredareas at this corner may occur and cause the formation of a smallaperture. While this is of little concern in the packaging of manyproducts, it may permit leakage of liquid products or those of finegranular form, such as activated carbon.

The present invention is designed to prevent this problem and permit thepackaging of fine granular or liquid products without leakage andwithout the use of additional or waste packaging material, but stillprovide the same strong, easily formed end seals disclosed in my saidco-pending application.

In forming the blanks for the bags of the present invention, one or moreplies of the blank are shaped slightly differently than the other ply orplies and thus, a small tab of material is provided at the criticalpoint of juncture of the transverse edge of the bag wall and thelongitudinal edge of the adjacent gusset. In this manner, rather thanthe effective sealing of the bag being dependent upon the maintenance ofcomplete adhesion at the bag corners, a positive seal, in the form of aply of packaging material, is provided at this point. In forming the plyof the bag blank providing these tabs, while the end of the ply isshaped slightly differently than the other ply or plies of the blank toprovide this extra tab, each end of the ply is identical but opposite tothe other end. Therefore, this ply may be formed from a continuous webwith no waste of packaging material and additionally, requires no morematerial than the other plies of the blank.

While at least one ply of the bag of the present invention is thus,shaped somewhat differently than the other ply or plies thereof, and,differently therefore than the plies of the bag disclosed in my saidco-pending application, the overall configuration of the bag issubstantially identical. Therefore, the same, simplified folding andsealing operations used to form the ends of the former bag may be usedwith that of the present invention. A

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continuous, multi-ply web of bag blanks formed in the manner of thepresent invention is, therefore, ideally suited for use in continuous,automatic packaging apparatus where simplicity of forming operations areessential.

The present invention, therefore, provides a multi-wall bagincorporating positive seals in its end closures.

Additionally, the ply or plies providing these seals may be formed froma continuous web of packaging materialwithout Waste of the material.

Further, the formation of the ply or plies providing the end sealsrequires no more packaging material than the formation of the plieslacking this feature and hence, results in no increase in materialcosts.

It will also be noted that the closing of the bag incorporating thispositive seal may be simply accomplished; thereby rendering the bagideally suited for use in automatic packaging apparatus.

These and other features and advantages of the present invention willbecome apparent from the following detailed description wherein:

FIGURE 1 illustrates the manner in which a web of multi-wall bag blanksare formed;

FIGURE 2 is a view of a portion of a web of bag blanks;

FIGURE 3 is an exploded view showing a seal-providing ply of themulti-wall bag blank separated from the other plies thereof;

FIGURE 4 is a view of the assembled bag blank folded into tubular formwith the ends of the tube open;

FIGURE 5 is an enlarged view of a portion of the bag showing details ofthe corner construction thereof; and

FIGURE 6 is another enlarged view of a portion of a bag showing moreclearly the manner in which the positive seals are provided at thecorners of the bag.

Referring to FIGURE 1 of the drawings, there is therein somewhatschematically illustrated the manner in which a web, in roll form, ofmulti-wall bag blanks is formed. As therein shown, a plurality of rolls,supplying webs 1, 2, and 3 of packaging material, are placed on unwindstands (not shown) from whence the webs are led through perforators 4, 5and 6.

Each of the perforators 4, 5 and 6 may conveniently be of the rollertype wherein one of the rollers carries a plurality of perforatingknives and the other roller a plurality of matching sockets; the knivesand sockets being distributed about the periphery of the rollers in amanner such that the desired perforation pattern is impressed on thematerial passing therebetween. The particular type of perforatingequipment used, however, does not form a part of the present inventionand any suitable type, therefore, may be used.

As each web passes through its associated perforator, a pattern ofperforations is formed therein outlining the shape of the bag ply. Thus,in the present embodiment, perforators 5 and 6 may produce a series ofperforations outlining plies 7 and 8 (see FIGURE 3) while perforator 4may be used to produce the blanks of ply 9. From perforators 4 and 5,respectively, the associated webs 1 and 2 are passed through crosspasting units 10 and 11 where adhesive is applied to the underside ofeach of the webs at spaced locations. Since it is not necessary to applyadhesive to web 3, it is merely passed around a turning roller 12 andthence, to the combining rolls 13 and 14 where the three webs 1, 2 and 3are joined to form a laminated web of bag blanks 15. It will beunderstood that the perforating and combining of the webs 1, 2 and 3 toform the laminated web 15 is suitably regulated to insure that theperforations in each of the webs 1, 2 and 3 are, for the most partaligned, and otherwise correctly positioned relative to one another, toform a laminated web of bag blanks. The laminated web 15 is then ledfrom the combining rollers 13 and 14 to a. rewind stand,

Where it is wound into roll form for convenient storage, shipment andsubsequent use. 7

It should be noted that in the formation of the laminated web 15, eachof the rolls of packaging material are offset axially of one another toprovide the staggered longitudinal edges shown in FIGURE 2. Thus, asshown in FIGURE 2 the longitudinal edge 16 of web 3 may be offset fromthe longitudinal edge 17 of web 2, which in turn is offset fro-m thelongitudinal edge 18 of web 1. Since the Webs are all of constant width,the opposite longitudinal edges, of course, will be offset in a similarbut reverse manner.

Turning now to FIGURE 3 of the drawings, there is therein shown atypical bag blank taken from the web of bag blanks shown in FIGURE 2 butwith the ply 9 formed from web 1 separated from the plies 7 and 8 tomore clearly show the different configuration of the transverse edges ofthe ply 9 relative to the plies 7 and 8. Plies 7 and 8, which areidentical except that the longitudinal edges thereof are displacedrelative to one another, each exhibit a front panel 19, a back panel,consisting of two back panel segments and 21, front gussets 22 and backgussets 23. Front gussets 22 are offset longitudinally from front panel19 to form steps 24 while back gussets 23 are offset from front gussets22 to form steps 25. Similarly, back panel portions 20 and 21 are offsetfrom back gussets 23 to form steps 26.

Ply 9, except for an important difference which will presently beexplained, is quite similar in construction to plies 7 and 8. Thus, ply9 exhibits a front panel 19, back panel portions 20 and 21, frontgussets 22' and back gussets 23. In ply 9, however, rather than theintersections of the longitudinal edges 27 of the back gussets 23 andthe transverse edges 28 of back panel portions 20' and 21' forming astep, as in the case of plies 7 and 8, the transverse edges 29 of backgussets 23 are extended to form tabs 30. Similarly, at the juncture ofthe longitudinal edges 31 of the front gussets 22 with the transverseedge 32 of the front panel 19, tabs 33 are provided for a purpose whichwill be presently explained. Since the ply 9 is formed from a continuousweb without waste between adjacent blanks, the provision of tabs and 33results in the removal of similarly shaped portions, as at 34 and 35,respectively, from the ends of the blank preceding and following it.

After formation of the Web 15 of multi-wall bag blanks, it may beshipped in this form for use in automatic packaging apparatus. Inapparatus of this type, the web is continuously shaped into a gusseted,tubular for-m, filled with the product to be packaged, the filledportion separated from the remainder of the tube along the transverseline of perforations, and the ends folded and sealed to form a filled,sealed bag. Alternatively, if the bag is to be filled and sealed bymanual or semi-automatic methods, the web is passed through a tuber andthen broken off at the lines of perforations to form a series ofopen-ended bags for subsequent manual or semi-automatic filling andsealing.

In either case, the resulting bag blank is eventually folded about theparallel, longitudinally extending fold lines 36-38 with the steppedlongitudinal edges thereof secured to one another, as shown in FIGURE 4,With gussets 22 and 23 folded inwardly between the front wall panel 19and back wall panel formed of back wall panel portions 20 and 21. Whenthus assembled, the removed portions or notches 34 and of the ply 9,which results from the provision of the tabs 33 and 30 on adjacentblanks, are backed by portions of the plies 7 and 8. Hence, the removalof these portions does not affect the sift-proof qualities of the bag.Additionally, since this portion of the bag blank will be folded over toform an end closure of the bag, the loss of one ply at this point in noway affects the overall strength of the bag. However, by the provisionof tabs, as at 39 and 33, a positive seal is provided at the corners ofthe bag.

This is perhaps more clearly shown in FIGURE 5, where the portion of acorner of a folded bag blank containing the tab 33 is shown in moredetail. Referring to FIGURES 4-6, it will be apparent that in use, thecontents of a filled bag will ordinarily extend within the bag up to thepoints indicated by the lines aa and bb, where the ends of the bag arefolded over to form an end closure. Without the provision of the tabs ofthe present invention, any separation between the outer surface of thebag and the inner surface of the adjacent gusset, as for example, atpoint 39, would allow leakage of the package material from the bag. Inthe bag of the present invention, however, a tab of material, as at 33in FIGURES 5 and 6, extends as a continuation of front gusset 22 ofinner ply 9 around the corner formed by the lower transverse edge of thefront wall panel and the longitudinal edge of the front gusset toprovide a positive seal at the ends of fold line b-b. Hence, when theends of a bag, namely those portions above and below, respectively, foldlines aa and bb, are folded over and secured to the rear and forwardsurfaces, respectively, of the bag, prevention of leakage at points 39is not dependent on adhesion alone since the tabs 30 and 33 effectivelyblock the passage of material in the bag past these corners even thoughsome separation of the adhered areas occurs.

It will thus be apparent that, through the present invention, a bagincorporating a positive seal at those points wherein leakage is mostlikely to occur has been provided at no increase in packaging materialand without affecting the overall strength and sift-proof qualities ofthe bag. Additionally, the same strong, easily formed end closuresdisclosed in my said co-pending application are retained in the presentconstruction.

While for purposes of illustration, a specific embodiment of myinvention has been disclosed, certain modifications within the scope ofthe invention will be apparent to those skilled in the art. For example,the number of plies may be varied to suit the requirements of theparticular use contemplated, and plies of the same or differentmaterials may be used as desired. Thus, the present invention isintended to be limited only within the scope of the appended claims.

I claim:

1. A multi-wall bag comprising:

(a) A plurality of superimposed plies,

(b) each ply comprising a front and back panel, a pair of front gussetsand a pair of back gussets,

(0) each of said front and back panels and said front and back gussetsbeing substantially rectangular in configuration,

(d) said front panel joining said front gussets along a common portionof their longitudinal edges with said front gussets being displacedlongitudinally of said front panel in a first direction,

(e) said back gussets each being joined to an adjacent front gussetalong a common portion of their longitudinal edges with said backgussets being displaced longitudinally of said front gussets in saidfirst direction,

(f) a back panel joining said back gussets along a common portion oftheir longitudinal edges with said back panel being displacedlongitudinally of said back gussets in said first direction,

(g) said front and back gussets of all of said plurality of plies beingsubstantially identical and coincident,

(h) said front and back panels of all of said plies being substantiallyidentical and coincident throughout a major portion of their extent withportions of at least one ply being nonidentical,

(i) said nonidentical portions in said one ply occurring adjacent theintersection of transverse edges of its front panels and back panelswith adjacent longitudinal edge of adjacent gussets,

(j) said nonidentical portions of said one ply comprising notches in twoadjacent corners of the front panel of said ply and tabs positionedadjacent the other corners of said front panel of said ply, and

(k) notches in two adjacent corners of the back panel of said one plyand tabs positioned adjacent the other corners of said back panel ofsaid ply.

2. The bag of claim 1 wherein:

(a) Said tabs have at least two sides thereof meeting at right angles,

(b) one of said sides of said tab being common to a portion of atransverse edge of a panel, and

(c) the other of said sides of said tab being common to a portion of alongitudinal edge of a gusset.

3. The bag of claim 2 wherein:

(a) Said notches have at least two sides thereof meeting at rightangles,

(b) one of said sides extending inwardly towards the center of a panelas a continuation of the transverse edge of an adjacent gusset, and

(c) the other of said sides extending from said one side to the adjacenttransverse edge of the panel in which it is formed.

4. The bag of claim 3 wherein:

(a) Said ply having nonidentical portions is the inner ply of the bag.

5. The bag of claim 4 wherein:

(a) Said sides of said notches and said tabs are substantially identicalin length.

6. An elongated web of packaging material comprising:

(a) A plurality of superimposed webs bonded together to form alaminated, multi-ply web,

(b) at least one of said superimposed webs having a first pattern ofperforations formed therein at constant intervals longitudinallythereof,

(0) the other of said superimposed webs having a second pattern ofperforations formed therein at constant intervals longitudinallythereof,

((1) said first and second patterns extending in first and secondstepped paths transversely of their associated webs,

(e) each of said patterns comprising pairs of first,

second and third portions and a fourth portion extending perpendicularlyto the longitudinal edges of said laminated web and pairs of fifth,sixth and seventh portions extending parallel to said longitudinal edgesof said laminated web,

(f) each of said fifth, sixth and seventh portions joining,respectively, a first and second, a second and third, and a third andfourth portion,

(g) said fifth, sixth and seventh portions of each of said patternsbeing substantially equal in length, (h) said second and third portionsof said first pattern being longer than said second and third portionsof said second pattern,

(i) said first and fourth portions of said second pattern being longerthan said first and fourth portions of said first pattern,

(j) said first and second patterns being substantially identical andcoincident throughout a major portion of their extent,

(k) other portions of said first and second patterns being nonidentical,and

(1) those portions of said first pattern which are nonidentical to saidsecond pattern outlining pairs of notches and tabs in the associatedsuperimposed web.

7. The elongated web of claim 6 wherein:

(a) Said tabs and said notches are substantially idenare disposed inspaced parallel relation to each other, and

(b) each of said superimposed webs are of substan tially constant width.

8. The elongated Web of claim 7 wherein:

(a) Said tabs and said notches are substantially identical in shape.

9. The elongated web of claim 8 wherein:

(a) Said tabs are substantially rectangular in shape.

References Cited by the Examiner UNITED STATES PATENTS 392,964 11/1888McCulla. x.,582,286 1/ 1952 Schenck 229-62 2,757,855 8/ 1956 Allen229-62 2,875,944 3/1959 Dufiin 229- FRANKLIN T. GARRETT, PrimaryExaminer.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,217,970 November 16, 1965 Burke P. Lokey It is hereby certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

Column 6, line 24, strike out "Said tabs and said notches aresubstantially iden-" and insert instead The longitudinal edges of saidsuperimposed webs (SEAL) Attest:

ERNEST W. SWIDER Alta-sting Officer EDWARD J. BRENNER Commissioner ofPate s

1. A MULTI-WALL BAG COMPRISING: (A) A PLURALITY OF SUPERIMPOSED PILES,(BE EACH PLY COMPRISING A FRONT AHD BACK PANEL, A PAIR OF FRONT GUSSETSAND A PAIR OF BACK GUSSETS, (C) EACH OF SAID FRONT AND BACK PANELS ANDSAID FRONT AND BACK GUSSESTS BEING SUBSTANTIALLY RECTANGULAR INCONFIGURATION, (D) SAID FRONT PANEL JOINING SAID FRONT GUSSETS ALONG ACOMMON PORTION OF THEIR LONGITUDINAL EDGES WITH SAID FRONT GUSSETS BEINGDISPLACED LONGITUDINALLY OF SAID FRONT PANEL IN A FIRST DIRECTION, (E)SAID BACK GUSSETS EACH BEING JOINED TO AN ADJACENT FRONT GUSSET ALONG ACOMMON PORTION OF THEIR LONGITUDINAL EDGES WITH SAID BACK GUSSETS BEINGDISPLACED LONGITUDINALLY OF SAID FRONT GUSSETS IN SAID FIRST DIRECTION,(F) A BACK PANEL JOINING SAID BACK GUSSETS ALONG A COMMON PORTION OFTHEIR LONGITUDINAL EDGES WITH SAID BACK PANEL BEING DISPLACEDLONGITUDINALLY OF SAID BACK GUSSETS IN SAID FIRST DIRECTION, (G) SAIDFRONT AND BACK GUSSETS OF ALL OF SAID PLURALITY OF PILES BEINGSUBSTANTIALLY IDENTICAL AND COINCIDENT, (H) SAID FRONT AND BACK PANELSOF ALL OF SAID PLIES BEING SUBSTANTIALLY IDENTICAL AND COINCIDENTTHROUGHOUT A MAJOR PORTION OF THEIR EXTENT WITH PORTIONS OF AT LEAST ONEPLY BEING NONIDENTICAL, (I) SAID NONIDENTICAL PORTIONS IN SAID ONE PLYOCCURRING ADJACENT THE INTERSECTION OF TRAVERSE EDGES OF ITS FRONTPANELS AND BACK PANELS WITH ADJACENT LONGITUDINAL EDGE OF ADJACENTGUSSETS, (J) SAID NONIDENTICAL PORTIONS OF SAID ONE PLY COMPRISINGNOTCHES IN TWO ADJACENT CORNERS OF THE FRONT PANEL OF SAID PLY AND TABSPOSITIONED ADJACENT THE OTHER CORNERS OF SAID FRONT PANEL OF SAID PLY,AND (K) NOTCHES IN TWO ADJACENT CORNERS OF THE BACK PANEL OF SAID ONEPLY AND TABS POSITIONED ADJACENT THE OTHER CORNERS OF SAID BACK PANEL OFSAID PLY.